Weather plays an important role in spring-blooming fruit crops due to the combined effects on bee activity, flower opening, pollen germination, and fertilization. To determine the effects of weather on highbush blueberry, Vaccinium corymbosum L., productivity, we monitored bee activity and compared fruit set, weight, and seed number in a field stocked with honey bees, Apis mellifera L., and common eastern bumble bees, Bombus impatiens (Cresson). Flowers were subjected to one of five treatments during bloom: enclosed, open, open during poor weather only, open during good weather only, or open during poor and good weather. Fewer bees of all types were observed foraging and fewer pollen foragers returned to colonies during poor weather than during good weather. There were also changes in foraging community composition: honey bees dominated during good weather, whereas bumble bees dominated during poor weather. Berries from flowers exposed only during poor weather had higher fruit set in 1 yr and higher berry weight in the other year compared with enclosed clusters. In both years, clusters exposed only during good weather had >5 times as many mature seeds, weighed twice as much, and had double the fruit set of those not exposed. No significant increase over flowers exposed during good weather was observed when clusters were exposed during good and poor weather. Our results are discussed in terms of the role of weather during bloom on the contribution of bees adapted to foraging during cool conditions.

Predation, development, and oviposition experiments were conducted to evaluate Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) as a potential biological control agent for tomato russet mite, Aculops lycopersici (Massee) (Acari: Eriophyidae), which can be a serious pest of greenhouse tomatoes. Results showed that A, swirskii attacked all developmental stages of A. lycopersici and had a type II functional response at the prey densities tested. The attack rate and handling time estimates from the random predator equation were 0.1289/h and 0.2320 h, respectively, indicating that A. swirskii can consume 103.4 individuals per day. Predation rates of A. swirskii on A. lycopersici in the presence of alternative food sources such as pollen, first-instar thrips, or whitefly eggs were 74, 56, and 76%, respectively, compared with the predation rate on A. lycopersici alone. A. swirskii successfully completed their life cycle on either A. lycopersici or cattail (Typha latifolia L.) pollen. At 25°C and 70% RH, developmental time of female A. swirskii fed on A. lycopersici or on cattail pollen was 4.97 and 6.16 d, respectively, For the first 10 d after molting to the adult stage, A. swirskii fed on A. lycopersici had higher daily oviposition rate (2.0 eggs per day) than on pollen (1.5 eggs per day). From this laboratory study, it can be concluded that A. swirskii has promising traits as a predator against A. lycopersici and that their populations can be maintained using alternative food sources such as cattail pollen. We suggest that the effectiveness of A. swirskii against A. lycopersici under field conditions needs next to be investigated.

The insecticidal activity after field exposure of an aluminum-carboxymethylcellulose microencapsulated formulation of Bacillus thuringiensis israelensis (Bti) spore-toxin complex, with malachite green as photoprotective agent, was evaluated using third-instar Aedes aegypti (L.) larvae in laboratory bioassays in Veracruz, México. Four insecticide treatments and an untreated control were compared at low and high doses over 96 d of field exposure under full sun or full shade conditions: 1) microencapsulated Bti spore-toxin complex, 2) nonmicroencapsulated Bti spore-toxin complex, 3) a commercial Bti formulation, 4) a commercial formulation of temephos, and 5) an untreated control. The low and high doses corresponded to the LC₅₀ and LC₉₀ concentrations for the Bti insecticides and to 0.5 and 1.0 mg/liter for temephos; the corresponding values for the microencapsulated Bti and commercial Bti, estimated in this study, were 0.061 and 0.14 mg/ml and 0.13 and 0.30 mg/ml, respectively. Overall, the study demonstrated that microencapsulation with aluminum-carboxymethylcellulose improved the activity against Ae. aegypti larvae of B. t. israelensis spore-toxin complex over that of a nonmicroencapsulated spore-toxin complex and that the improvement was particularly important under full sun and high dose. Moreover, insecticidal activity of the microencapsulated B. thuringiensis israelensis spore-toxin complex was superior to that of a commercial B. thuringiensis israelensis formulation and comparable to that of the chemical insecticide temephos, Finally, it was suggested that the microencapsulated B. thuringiensis israelensis formulation should be evaluated for field use in Veracruz because its activity against Ae. aegypti larvae remained high through 31 d and this would allow halving of the current insecticide application frequency.

The production of a multiple nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), has been markedly increased by using juvenile hormone analog (JHA) technology to generate a supernumerary sixth instar in the species. In the current study we compared the incidence of cannibalism in S. exigua fifth and sixth instars reared at low (two larvae per dish) and a high density (10 larvae per dish). The incidence of cannibalism was significantly higher in fifth instars compared with sixth instars and increased with rearing density on both instars. Infected larvae were more prone to become victims of cannibalism than healthy individuals in mixed groups comprising 50% healthy 50% infected larvae in both instars reared at high density. Instar had a marked effect on occlusion body (OB) production because JHA-treated insects produced between 4.8- and 5.6-fold increase in OB production per dish compared with fifth instars at high and low densities, respectively. The insecticidal characteristics of OBs produced in JHA-treated insects, as indicated by LD₅₀ values, were similar to those produced in untreated fourth or fifth instars. Because JHA technology did not increase the prevalence of cannibalism and had no adverse effect on the insecticidal properties of SeMNPV OBs, we conclude that the use of JHAs to generate a supernumerary instar is likely to be compatible with mass production systems that involve gregarious rearing of infected insects.

We integrated a natural enemy survey of the broader landscape into a more traditional survey for Aphis glycines Matsumura (Hemiptera: Aphididae), parasitoids and predatory flies on soybean using A. glycines-infested soybean, Glycine max (L.) Merr., placed in cropped and noncropped plant systems to complement visual field observations. Across three sites and 5 yr, 18 parasitoids and predatory flies in total (Hymenoptera: Aphelinidae [two species] and Bracondae [seven species], Diptera: Cecidomyiidae [one species], Syrphidae [seven species], Chamaemyiidae [one species]) were detected, with significant variability in recoveries detected across plant system treatments and strong contrasts in habitat affinity detected among species. Lysiphlebus testaceipes Cresson was the most frequently detected parasitoid, and no differences in abundance were detected in cropped (soybean, wheat [Triticum aestivum L.], corn [Zea mays L.], and alfalfa [Medicago sativa L.]) and noncropped (poplar [Populus euramericana (Dode) Guinier] and early successional vegetation) areas. In contrast, Binodoxys kellggensis Pike, Starý & Brewer had strong habitat affinity for poplar and early successional vegetation. The low recoveries seasonally and across habitats of Aphelinus asychis Walker, Aphelinus sp., and Aphidius colemoni Viereck make their suitability to A. glycines on soybean highly suspect. The widespread occurrence of many of the flies reflects their broad habitat affinity and host aphid ranges. The consistent low field observations of parasitism and predation suggest that resident parasitoids and predatory flies are unlikely to contribute substantially to A. glycines suppression, at least during the conventional time period early in the pest invasion when classical biological control activities are considered. For selected species that were relatively well represented across plant systems (i.e., L. testaceipes and Aphidoletes aphidimyza Rondani), conservation biological control efforts may be fruitful. The additional information gained from expanding the natural enemy survey into the broader landscape was essential in making these distinctions relevant to conservation biological control, while adding agroecosystem-specific information valuable to classical biological control.

Although current USDA-APHIS standards suggest that a core temperature of 71.1°C (160°F) for 75 min is needed to adequately sanitize emerald ash borer, Agrilus planipennis Fairmaireinfested firewood, it is unclear whether more moderate (and economical) treatment regimes will adequately eradicate emerald ash borer larvae and prepupae from ash firewood. We constructed a small dry kiln in an effort to emulate the type of technology a small- to medium-sized firewood producer might use to examine whether treatments with lower temperature and time regimes successfully eliminate emerald ash borer from both spilt and roundwood firewood. Using white ash (Fraxinus americana L.) firewood collected from a stand with a heavy infestation of emerald ash borer in Delaware, OH, we treated the firewood using the following temperature and time regime: 46°C (114.8°F) for 30 min, 46°C (114.8°F) for 60 min, 56°C (132.8°F) for 30 min, and 56°C (132.8°F) for 60 min, Temperatures were recorded for the outer 2.54-cm (1-in.) of firewood. After treatment, all firewood was placed under mesh netting and emerald ash borer were allowed to develop and emerge under natural conditions. No treatments seemed to be successful at eliminating emerald ash borer larvae and perpupae as all treatments (including two nontreated controls) experienced some emerald ash borer emergence. However, the 56°C (132.8 F) treatments did result in considerably less emerald ash borer emergence than the 46°C (114.8°F) treatments. Further investigation is needed to determine whether longer exposure to the higher temperature (56°C) will successfully sanitize emerald ash borer-infested firewood.

Fraxinus spp. logs infested with Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) were fumigated with sulfuryl fluoride (SF) in 432-liter chambers at 15.6 and 21.1°C for 24 and 48 h. Concentration × time (CxT) exposures (g-h/m³) of SF obtained were 3,382 (24-h exposure) and 5,466 (48-h exposure) at 15.6°C and 3,329 (24 h) and 4,385 (48-h exposure) at 21.1°C after doses of 144, 128, 128, and 104 g/m³, respectively. After aeration, logs were placed in modified fiber drums for 8 wk to capture emerging beetles. No adults emerged from any of the fumigated logs, whereas 933 adults emerged from control logs. Eggs were fumigated at CxT exposures similar to log fumigations (3,240 and 4,262 g-h/m³, respectively) and again at doses 16 g/m³ lower, at 21.1°C for 24 and 48 h. No hatch was observed at CxT dosages >4.262 g-h/m³. No larvae continued development on artificial diet after hatching from eggs fumigated at all tested dosages, whereas 10 control larvae developed to instar I or II. Chamber fumigations with 31 and 46% load factors provided additional sorption and concentration data. A. planipennis-infested logs in tarped, 149.1-m³ cargo containers were fumigated at dosages used in successful trials. Logs were monitored for 8 wk for adult emergence. There was no adult emergence, but 621 adults emerged from a similar quantity of control logs. CxT dosages of SF for 100% control of A. planipennis at 15.6 and 21.1°C for 24- and 48-h exposure can be obtained under commercial fumigation conditions. A quarantine treatment schedule for SF is proposed.

Low pressure treatment in flexible polyvinyl chloride containers is a potential alternative to chemical fumigants for California tree nuts. Laboratory studies investigated the effect of relative humidity and product moisture on weight loss and mortality of diapausing and nondiapausing larvae of the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), exposed to 50 mmHg. Diapausing larvae were far more tolerant than nondiapausing larvae to low pressure; exposure times nearly twice those of nondiapausing larvae were required to obtain comparable weight loss or mortality levels in diapausing larvae. Relative humidity was found to have a large effect on both weight loss (assumed to be due to moisture loss) and mortality of both nondiapausing and diapausing larvae. Mortality and weight loss increased as humidity levels decreased. By controlling the relative humidity of the treatment chamber, product moisture also strongly affected weight loss and mortality. The results suggest that for tree nuts, product moisture levels may affect the efficacy of low pressure treatments.

The citrus mealybug, planococcus citri (Risso) (Hemiptera: Pseudococcidae), is the main grapevine pest in vineyards in some countries, such as Spain and Brazil. In Galician vineyards (northwestern Spain), mealybug population levels are low because the accumulated degree-days are lower than in other grapevine-growing areas. The main problem caused by mealybugs is the transmission of viruses, even at low infestation levels. The active period of citrus mealybug in the study vineyard lasted from July until December, with an important movement peak at the end of July and August and a lower peak in November. The mealybug mainly moved upward along arbor-trained plants, and there were no important downward movements at the end of the season as has been described for other grapevine mealybugs. The mealybugs were normally restricted to the woody organs and were only present on leaves, branches, and green canes (always close to woody parts) in plants with high infestations. The movement of mealybugs between plants does not seem to take place by contact between green organs. Passive aerial transport and movement of pruning remains may play an important role in mealybug movement and thus in spread of the virus. The number of mealybugs carrying Grapevine leafroll-associated virus 3 (GLRaV-3) was found to represent ≈75% of mealybugs caught in a GLRaV-3 infected vineyard.

Thrips cause considerable economic loss to mango, Mangifera indica L., in Penang, Malaysia. Three nondestructive sampling techniques—shaking mango panicles over a moist plastic tray, washing the panicles with ethanol, and immobilization of thrips by using CO₂—were evaluated for their precision to determine the most effective technique to capture mango flower thrips (Thysanoptera: Thripidae) in an orchard located at Balik Pulau, Penang, Malaysia, during two flowering seasons from December 2008 to February 2009 and from August to September 2009. The efficiency of each of the three sampling techniques was compared with absolute population counts on whole panicles as a reference. Diurnal flight activity of thrips species was assessed using yellow sticky traps. All three sampling methods and sticky traps were used at two hourly intervals from 0800 to 1800 hours to get insight into diurnal periodicity of thrips abundance in the orchard. Based on pooled data for the two seasons, the CO₂ method was the most efficient procedure extracting 80.7% adults and 74.5% larvae. The CO₂ method had the lowest relative variation and was the most accurate procedure compared with the absolute method as shown by regression analysis. All collection techniques showed that the numbers of all thrips species in mango panicles increased after 0800 hours, reaching a peak between 1200 and 1400 hours. Adults thrips captured on the sticky traps were the most abundant between 0800–1000 and 1400–1600 hours. According to results of this study, the CO₂ method is recommended for sampling of thrips in the field. It is a nondestructive sampling procedure that neither damages flowers nor diminishes fruit production. Management of thrips populations in mango orchards with insecticides would be more effectively carried out during their peak population abundance on the flower panicles at midday to 1400 hours.

The most effective traps for capturing cerambycids and other saproxylic beetles are intercept designs such as funnel traps and cross-vane panel traps. We have observed that adult cerambycids of many species often alight and walk upon panel traps, and few are actually captured. In an effort to improve trap capture and retention, researchers have treated intercept traps with Rain-X, a polysiloxane formulation that renders surfaces more slippery. Here, we summarize experiments that compared the efficacies of Rain-X and Fluon, a PTFE fluoropolymer dispersion, as surface treatments for panel traps that are deployed to capture cerambycid beetles, using untreated traps as controls. Fluon-treated traps captured on average >14× the total number of beetles, and many more cerambycid species, than were captured by Rain-X-treated or control traps. Beetles captured by Fluon-treated traps ranged in body length by 350%. They could not walk on vertical panels treated with Fluon but easily walked on those treated with Rain-X and on untreated traps. Moreover, a single Fluon treatment remained effective for the entire field season, even in inclement weather. We conclude that treating panel traps with Fluon greatly improves their efficiency in capturing cerambycid beetles. This increased efficacy will be particularly important when traps are deployed to detect very low-density populations, such as incursions of exotic species, or remnant communities of rare and endangered species. The influence of Fluon on trap efficiency may vary with product formulation and its source and also with climatic conditions.

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an exotic pest of soybean, Glycine max (L.) Merr., in North America. Plant resistance to the soybean aphid was recently discovered in ‘Dowling’ soybean in 2005. Dowling exhibits strong antibiotic effects on the soybean aphid by limiting colonization and effectively controlling aphid population development during all soybean growth stages. In addition, aphids feeding on Dowling experienced significantly reduced survival, longevity, and fecundity and increased developmental times. An assessment of soybean aphid feeding behavior was compared on Dowling and the susceptible check ‘Glenwood’ by using the electrical penetration graph technique. The effects of plant resistance on aphid feeding behavior were analyzed by comparing the amount of time soybean aphid spent feeding on various plant tissues on resistant and susceptible plants. There was no significant difference in the initial time for the aphid to begin probing on resistant and susceptible plants indicating no adverse effect of plant exterior on the soybean aphid attempting to feed. However the time from the beginning of plant penetration by the stylets to the first phloem sieve element phase was significantly different. In aphids that successfully reached phloem on Dowling, the time taken to reach this phase was triple the time of aphids reaching the phloem sieve element on the susceptible line. In addition, the total number of probing events and the duration of nonprobing were not significantly different between Dowling and Glenwood. When comparing feeding between lines, a greater proportion of aphids showed ingestion of xylem when feeding on Dowling, whereas successful feeding on phloem on Dowling was significantly shorter than when feeding on the susceptible line. Therefore, the antibiotic effect of Dowling resistance seems to reside at the level of the phloem sieve element, prohibiting the aphid from successfully exploiting phloem, and as a consequence the aphid abandons the Dowling plant or dies of inadequate nutritional intake.

Sex pheromone monitoring lures from five different commercial sources were compared for their attractiveness to male diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) in canola, Brassica napus L., fields in western Canada. Lures that had the highest pheromone release rate, as determined by aeration analyses in the laboratory, were the least attractive in field tests. Lures from all the commercial sources tested released more (Z)-11-hexadecenal than (Z)-11-hexadecenyl acetate and the most attractive lures released a significantly higher aldehyde to acetate ratio than less attractive lures. Traps baited with sex pheromone lures from APTIV Inc. (Portland, OR) and ConTech Enterprises Inc. (Delta, BC, Canada) consistently captured more male diamondback moths than traps baited with lures from the other sources tested, In two different lure longevity field trapping experiments, older lures were more attractive to male diamondback moths than fresh lures. Pheromone release from aged lures was constant at very low release rates. The most attractive commercially available sex pheromone lures tested attracted fewer diamondback moth males than calling virgin female moths suggesting that research on the development of a more attractive synthetic sex pheromone lure is warranted.

The toxicity and sublethal effects of methoxyfenozide were evaluated in third instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), that fed on contaminated semisynthetic diet. The LC₅₀ value was estimated at 0.23 mg of active ingredient (AI)/kg diet (range, 95% CI: 0.17–0.37) at 264 h after treatment. The effects on development, survival, and reproduction were observed in third instars of this pest that survived exposure to an LC₂₅ concentration of methoxyfenozide. The larvae from the insecticide treatment exhibited lower pupal weights, an increase in both larval and pupal developmental times and a higher frequency of malformations of the wings in adults than untreated larvae. Adults from the methoxyfenozide treatment did not show reduced fecundity (mean cumulative number of eggs laid per female), but fertility as measured by the percentage of eggs hatched (fertility) was significantly reduced compared with untreated control insects. No significant effects were observed on pupal sex ratio. We concluded that the lethal and sublethal effects of methoxyfenozide are likely to have a significant impact on S. exigua populations on treated crops.

Wild bee conservation is regarded as essential for sustainable production of pollinator dependent crops, yet little is known about the effects on wild bee communities of typical insect pest management programs used postbloom. We developed an insecticide program risk (IPR) index to quantify the relative risk to wild bees of insecticide programs applied to blueberry fields. This was used to determine the relationship between IPR and the abundance, diversity, and richness of wild bee communities sampled during three successive flowering seasons. In 2 of 3 yr, bee abundance and species richness declined with increasing IPR. Bee diversity declined with IPR in one of 3 yr. These results indicate that wild bee communities are negatively affected by increasingly intensive chemical pest management activities in crop fields and that interyear variability in bee populations has the potential to mask such effects in short-term studies. When several wild bee species were analyzed separately, two of three solitary and one of three social blueberry-foraging species declined with increasing IPR values, suggesting that different life histories and nesting habits may help some bee populations escape the negative effects of insecticides applied after bloom. Pollinator conservation programs aimed strictly at reducing insecticide use may have varying success, depending on the biology of the target bee species. The IPR index provides a standard method to compare pest management programs for their potential effect on wild bee communities, with broad application for use in other agricultural systems.

The current study compared the toxicity of different concentrations of boric acid in adult workers of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae), with toxicological bioassays, and examining the dose-dependent and time-dependent histopathological changes, of the midgut, Malpighian tubules, and postpharyngeal glands. Our results revealed the importance of conducting toxicological bioassays combined with morphological analyses of the organs of ants chronically exposed to insecticides used in commercial ant baits. In vitro bioassays showed that boric acid significantly decreases the survivorship of workers regardless of concentration, whereas the morphological data suggested progressive dose-dependent and time-dependent changes in the organs examined, which were evident in the midgut. The midgut is the first organ to be affected, followed by the postpharyngeal gland and Malpighian tubules. This sequence is in agreement with the absorption pathway of this chemical compound in the midgut, its transference to the hemolymph, possibly reaching the postpharyngeal glands, and excretion by the Malpighian tubules. These progressive changes might be due to the cumulative and delayed effect of boric acid. Our findings provide important information for the understanding of the action of boric acid in ant baits in direct and indirect target organs.

The pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), has been a major pest of pea, Pisum sativum L., in eastern Washington and northern Idaho since its introduction to the region in the early 1970s. Eggs are deposited in the spring on the soil surface and first instars hatch and move to pea root nodules, where larvae feed before they pupate and adults emerge in mid- to late summer. No-tillage practices are known to reduce pea leaf weevil colonization in pea, but the effects of tillage on larval densities and subsequent adult emergence have not been examined. During 2005, 2006, and 2007, we compared densities of colonizing adult and immature pea leaf weevils on pea plots grown using conventional tillage and no-tillage. In 2005 and 2006, emergence of adult pea leaf weevil was monitored in the same plots. Densities of colonizing adult and immature pea leaf weevil were significantly higher in conventional tillage plots. Larvae in conventional tillage were further along in development than larvae in no-tillage plots during June and July. Densities of emerging adult pea leaf weevil were significantly greater from conventional tillage than no-tillage plots. Based on densities of colonizing and subsequent emerging adults, survival of weevils from egg through adult was greater in conventional tillage plots, Soils under no-tillage are cooler, resulting in later emergence of the pea crop and delayed root nodule development, possibly affecting the ability of first-instar pea leaf weevil to locate host plant roots. Our results indicate no-tillage fields are less suitable for pea leaf weevil colonization and survival than conventional tillage fields.

Semiochemical-based exotic species surveys targeting forest Coleoptera have gradually expanded in North America and elsewhere. Determining how various factors affect trap catches and increase species richness in traps is important for maximizing the efficacy of survey efforts. Studies were conducted in southern Maine and New Hampshire by using ethanol and α-pinene as lures to determine the influence of trap type, lure placement and size, and habitat type on catches of Scolytinae and Cerambycidae in coniferous forests. Three trap types (canopy malaise, intercept panel, and multiple-funnel), three lure placements/sizes (standard placement, above trap, and enlarged), and two habitat types (margins of clearcuts and shelterwood) were tested in three experiments. The three trap types performed equally well in terms of average number of species captured, but the canopy malaise caught more unique species than the other traps. In most cases, traps with lures placed above traps caught fewer beetles than lures hanging from the side of traps or with an expanded surface area. Generally, more insects were captured in shelterwood treatments versus the margins of clearcuts.

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive pest discovered in North America in 2002, is now well established and threatens ash (Fraxinus spp.) trees throughout the continent. Experiments were conducted to 1) examine the efficacy of an alternative natural pesticide, azadirachtin, to control emerald ash borer, and 2) determine foliar uptake and dissipation patterns after systemic injections of azadirachtin into trunks of small (2.2 cm diameter at breast height [dbh]), uninfested green ash trees. We found no evidence of mortality of adult beetles. In contrast, fewer larvae completed their development at dose levels ≥1.7 mg (AI)/cm dbh and development ceased beyond the second instar at dose levels ≤13.6 mg (AI)/cm dbh. Substantial concentrations (11.2 µg/g dry mass [SD = 7.55]) of azadirachtin were present in leaves within 7 d of treatment. After rapid initial uptake, concentrations in leaves declined logarithmically during the 55 d after injection. A similar pattern was observed in a separate experiment that examined the uptake and translocation of azadirachtin in larger green ash trees (22 cm dbh) treated with 250 mg (AI)/cm dbh with the EcoJect injection system. In another experiment, recently infested plantation green ash trees treated with doses ≥40 mg (AI)/cm dbh had significant reductions in adult emergence ≈1 yr postinjection. Given the inhibition of larval development, reduction of adult emergence, and the occurrence of foliar residues at biologically active concentrations, we conclude that azadirachtin is effective in protecting ash trees from emerald ash borer.

Trees in the genus Populus can provide substantial commercial and ecological benefits, including sustainable alternatives to traditional forestry, Realization of this potential requires intensive management, but damage by defoliating insects can severely limit productivity in such systems. Two approaches to limiting these losses include cultivation of poplar varieties with inherent resistance to pests and application of microbial pesticides. Little is known about the interaction between host resistance and the ability of poplars to support the efficacy of biocontrol agents. The research described here was conducted to survey the effect of hybrid poplar clones on gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), a pest on these trees. We assessed the effect of various poplar clones on larval performance and susceptibility to Bacillus thuringiensis subsp, kurstaki. Larvae were reared from hatching on the foliage of 25 hybrid poplar clones and we monitored larval survival, development time, and weight at fourth instar. Eight of these clones showed high resistance against gypsy moth. The remaining clones showed high variation in their effect on larval performance. We evaluated the susceptibility of third-instar larvae to B. thuringiensis subsp, kurstaki when reared on the 17 remaining clones. There was a significant effect of poplar clone on time to death after ingestion of B. thuringiensis subsp. kurstaki. The susceptibility of gypsy moth larvae to B. thuringiensis on various clones was not correlated with the effects of these clones on larval performance in the absence of B. thuringiensis, suggesting this interaction is more complex than merely reflecting higher mortality to previously stressed larvae.

The southern chinch bug, Blissus insularis Barber (Hemiptera: Blissidae), is the most destructive insect pest of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze. Management of B. insulaiis has depended on frequent insecticide applications, which has resulted in populations becoming resistant to several insecticide classes. To facilitate developing a resistance management program for this pest, it is necessary to develop methods to rear insects of known age, generation, and pesticide exposure history. Synchronized rearing methods were developed after testing five different laboratory methods. The use of glass jars and a combined diet of fresh corn, Zea mays L., cob and St. Augustinegrass proved to be best for producing B. insuhris of known age and generation. Body size was consistent over nine generations of rearing. Production of a high proportion of brachypterous B. insuhris (the nondispersal adult form) also suggests that populations were not stressed during laboratory rearing. This work presents the first successful synchronized rearing method for B. insuhris.

Field observations from pecan, Carya illinoinensis (Wangenh.) Koch, orchards in Texas were used to develop and validate a degree-day model of cumulative proportional adult flight and oviposition and date of first observed nut entry by larvae of the first summer generation of the pecan nut casebearer, Acrobasis nuxvorella Nuenzig (Lepidoptera: Pyralidae). The model was initiated on the date of first sustained capture of adults in pheromone traps. Mean daily maximum and minimum temperatures were used to determine the sum of degree-days from onset to 99% moth flight and oviposition and the date on which first summer generation larvae were first observed penetrating pecan nuts. Cumulative proportional oviposition (y) was described by a modified Gompertz equation, y = 106.05 × exp(-(exp(3.11 - 0.00669 × (x - 1)))), with x = cumulative degree-days at a base temperature of 3.33°C. Cumulative proportional moth flight (y) was modeled as y = 102.62 × exp(-(exp(l.49 - 0.00571 × (x - 1)))). Model prediction error for dates of 10, 25, 50, 75, and 90% cumulative oviposition was 1.3 d and 83% of the predicted dates were within ± 2 d of the observed event. Prediction error for date of first observed nut entry was 2.2 d and 77% of model predictions were within ± 2 d of the observed event. The model provides ample lead time for producers to implement orchard scouting to assess pecan nut casebearer infestations and to apply an insecticide if needed to prevent economic loss.

The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of peaches, Prunus persica (L.) Batsch, in North America. We evaluated the effectiveness of two widely used trap types (pyramid versus Circle traps) and commercially available synthetic lures for monitoring the pest in two peach orchards in Alabama during 2008 and 2009. The lures evaluated alone or in combinations included benzaldehyde (BZ) (a component of fruit odor), plum essence (PE) (a mixture of fruit odor extracted from food grade plum), and grandisoic acid (GA) (a male-produced aggregation pheromone of plum curculio). In general, pyramid traps captured more plum curculio adults than Circle traps, particularly during the first generation. Trap performance was improved numerically by the addition of BZ, PE, or GA alone (single lures) and was significantly enhanced by the addition of the combined BZ PE lure. In both first and second generations, the combined BZ PE lure increased plum curculio captures (significant in some trials) over unbaited traps and traps baited with single lures by ≈ 1.5–21-fold and had the highest response indices (RIs), which is indicative of high attractiveness. The combined BZ GA lure and the three-component BZ PE GA lure also captured numerically more plum curculio adults than unbaited traps or traps baited with single lures but the differences were rarely significant. Analysis of ratios of interaction suggests the possibility of synergistic interactions between BZ and PE and between BZ and GA; however, additive effects were concluded due to high sample errors. These results are discussed in relation to the physicochemical properties of the lures and the potential of using baited monitoring traps to aid plum curculio management decisions in peach orchards.

Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Both immobilization and mortality occurred most quickly with bifenthrin, followed by thiamethoxam, chlorfenapyr, and fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30°C, with three ratios of topically treated donor ant corpses to live recipients (5, 10, or 20% donors). Bifenthrin had the greatest horizontal activity of the chemicals tested. For chlorfenapyr, the only treatments having higher mortality than controls were the highest percentage donors at either 10 or 30°C. Horizontal activity of fipronil was temperature dependent only with the highest proportion of donors and was lower than that of bifenthrin but higher than that of chlorfenapyr or thiamethoxam. Mean mortality due to thiamethoxam was similar to that with chlorfenapyr. Significant mortality occurred in all of the 20 and 30°C thiamethoxam treatments, but none of the 10°C treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control bridge. Mortality data suggest that a reduction in recruitment rather than repellency account for this result.

Onset of abnormal behaviors, morbundity, and death was evaluated in eastern subterranean termites, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), exposed to several concentrations (45, 90, 135, and 180 ppm) of indoxacarb and to several (5, 10, 20, 40, 80, and 160 min) exposure periods. Abnormal behaviors, morbundity, and death occurred in a predictable sequence: disorientation, ataxia, and morbundity followed by death. In general, higher concentrations and longer exposure periods resulted in faster onset of abnormal behaviors, morbundity, and death. The average onset time of abnormal behaviors, morbundity, and death was faster for groups of termites compared with individuals exposed to similar concentrations and periods of contact. The importance of onset times of abnormal behaviors as another important measure of the toxicity of slow-acting toxicants is discussed.

The objective of this study was to evaluate lufenuron termite bait (1,500 ppm) for the elimination of colonies of Reticulitermes hesperus Banks (Isoptera: Rhinotermitidae). Dispersion of colonies in six baited and six unbaited sites near Placerville, CA, was determined by genetic (microsatellite) analyses. Twenty-one colonies of R. hesperus inhabited the six baited sites and eight colonies of R. hesperus occurred in the six unbaited sites. Five criteria provided a cause-and-effect link between the deployment of lufenuron termite bait and elimination of baited colonies: 1) association of foragers, as members of the same colony, in the independent monitoring stations and bait stations; 2) quantity of bait consumed; 3) abnormal physical appearance of foragers in bait stations; 4) disappearance of foragers from, and cessation of feeding in, independent monitoring stations visited by baited colonies; and 5) presence of foragers from, and continuation of feeding in, independent monitors visited by unbaited colonies. Baited colonies were devoid of foraging termites within a mean of 70.6 d (range, 37–93 d) of bait deployment. Colonies consumed a mean of 8.0 g of bait (range, 2.2–16.0 g). Wood consumption by baited and unbaited colonies was not significantly different during the 2 mo before baiting, 281.4 versus 590.5 mg/d per colony, respectively, nor during the 3 mo immediately after baiting, 112.5 versus 436.8 mg/d per colony, respectively. However, from 10 to 16 mo after baiting, wood consumption by baited colonies essentially ceased and was significantly less than the unbaited colonies, 7.9 versus 470.1 mg/d per colony, respectively.

The fumigant toxicity of 12 essential oil components [carvacrol, 1,8-cineole, trans-cinnamaldehyde, citronellic acid, eugenol, geraniol, S-(-)-limonene, (-)-linalool, (-)-menthone, ( )-α-pinene, (-)-β-pinene, and thymol] to adult male, adult female, gravid female, and large, medium, and small nymphs of the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), was determined. 1,8-Cineole was the most toxic essential oil component to adult males and females, gravid females, and large nymphs, with LC₅₀ values of 6.8, 8.4, 5.3, and 11.4 mg/liter air at 24 h, respectively. (-)-Menthone and carvacrol were the most toxic essential oil components to medium and small nymphs, with LC₅₀ values of 9.0 and 3.6 mg/liter air at 24 h, respectively. Citronellic acid was the least toxic essential oil component to all stages of the German cockroach. There was not a consistent relationship between body mass and toxicity; the susceptibility of the stages differed for each oil. LC₅₀ values of all stages were correlated negatively with vapor pressure and positively with molecular weight of the essential oil components. The most toxic essential oil components to the majority of cockroach stages were cyclic aliphatic hydrocarbons [1,8-cineole, (-)-menthone, ( )-α-pinene, (-)-β-pinene, and S-(-)-limonene]. Ring size and the presence of a carbonyl functional group also may have contributed to the toxicity of the compounds. Citronellic acid had no effect on ootheca hatch (100% hatch), whereas (-)-menthone had the greatest effect on ootheca hatch (73% hatch). Percentage of hatched oothecae decreased linearly with increasing concentration for (-)-menthone, S-(-)-limonene, ( )-α-pinene, and (-)-β-pinene. No essential oil component prevented ootheca hatch, suggesting that multiple treatments would be required in the field to eliminate infestations.

We determined the impact of imidacloprid (Premise) on colonies of Reticulitermes spp. (Isoptera: Rhinotermitidae) through soil applications in the field. We selected 11 houses in the Raleigh, NC, area with active termite infestations. In-ground monitoring stations (mean = 75.9 stations) were installed around each house, and samples of termites visiting the monitors, in mud tubes, as well as samples from wood debris in the yard, were collected monthly for up to 14 mo to determine the numbers and locations of colonies present before treatment. We used microsatellite genetic markers to identify individual colonies present on each property. All houses were treated with Premise 75 WSP by using an exterior perimeter/interior spot treatment. After treatment, termite samples were collected monthly for 3 mo and then quarterly for 2 yr to track the fate of colonies. Of the 12 treated colonies (those attacking structures), 75% disappeared within 90 d and were not detected again. In contrast, only 25% of 48 untreated colonies (located 2 m or further from the treatment zone) and 40% of the six likely treated colonies (located within 0.5 m of the treatment zone but not known to be attacking the structure) were not detected again during the study. Our findings are consistent with strong colony-level effects of soil treatments with imidacloprid, resulting in the suppression or elimination of Reticulitermes spp. colonies in many cases.

This study examined the influence of soil type and moisture availability on termite foraging behavior. Physical properties of the soil affected both tunneling behavior and shelter tube construction. Termites tunneled through sand faster than top soil and clay. In containers with top soil and clay, termites built shelter tubes on the sides of the containers. In containers with sand, termites built shelter tubes directly into the air and covered the sides of the container with a layer of sand. The interaction of soil type and moisture availability affected termite movement, feeding, and survival. In assays with moist soils, termites were more likely to aggregate in top soil over potting soil and peat moss. However, termites were more likely to move into containers with dry peat moss and potting soil than containers with dry sand and clay. Termites were also significantly more likely to move into containers with dry potting soil than dry top soil. In the assay with dry soils, termite mortality was high even though termites were able to travel freely between moist sand and dry soil, possibly due to desiccation caused by contact with dry soil. Evaporation from potting soil and peat moss resulted in significant mortality, whereas termites were able to retain enough moisture in top soil, sand, and clay to survive for 25 d. The interaction of soil type and moisture availability influences the distribution of foraging termites in microhabitats.

In a previous experimental study, recluse spiders Loxosceles reclusa Gertsch and Mulaik and Loxosceles laeta (Nicolet) (Araneae: Sicariidae) preferred small cardboard refugia covered with conspecific silk compared with never-occupied refugia. Herein, we investigated some factors that might be responsible for this preference using similar cardboard refugia. When the two Loxosceles species were given choices between refugia previously occupied by their own and by the congeneric species, neither showed a species-specific preference; however, each chose refugia coated with conspecific silk rather than those previously inhabited by a distantly related cribellate spider, Metaltella simoni (Keyserling). When L. laeta spiders were offered refugia that were freshly removed from silk donors compared with heated, aged refugia from the same silk donor, older refugia were preferred. Solvent extracts of L. laeta silk were chosen approximately as often as control refugia when a range of solvents (methylene chloride:methanol, water, and hexane) were used. However, when acetone was used on similar silk, there was a statistical preference for the control, indicating that there might be a mildly repellent aspect to acetone-washed silk. Considering the inability to show attraction to chemical aspects of fresh silk, it seems that physical attributes may be more important for selection and that there might be repellency to silk of a recently vacated spider. These findings are discussed in regard to pest management strategies to control recluse spiders.

The pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is a relevant pest of pear, Pyrus communis L., trees in Emilia-Romagna region (northern Italy). The susceptibility to the insecticide abamectin was evaluated at different times of the year on C. pyri populations undergoing different control strategies within conventional, integrated, and organic farms. The tests performed were the egg spray and the topic and dip bioassay on adults. The larval mortality was evaluated by dip bioassay on treated leaves. The activity of P450-dependent monooxygenases, a relevant enzyme system involved in insecticide resistance of C. pyri, was also determined in adults by 7-ethoxycoumarin O-deethylation (ECOD assay). Tests on treated eggs and on larvae showed no significant differences in LC₅₀ and LC₉₀, although these values were always lower in individuals collected from organic farms in comparison with all other farms. Tests on overwintering adults revealed differences among populations, probably more related to collection time than to field pest control strategies. Unexpectedly, the ECOD assay on adults showed a slightly higher cytochrome P450 monooxygenase activity in the population undergoing organic control in comparison to others. Our results indicate that egg spray is the most reliable bioassay to verify data of open-field applications. Apparently, no resistance to abamectin has yet been developed by C. pyri in Emilia-Romagna.

Insect natural enemies can develop resistance to insecticides in the field like their host insects. Recently, a high level of resistance to several groups of insecticides from Pakistan has been shown in Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). Here, we were interested to determine the impact of insecticides resistance on fitness of various populations of C. carnea collected over three consecutive years (2005–2007) from different areas of Pakistan. The populations were examined for intrinsic rate of population increase, growth index, fertility, eggs viability, survival to adult hood and doubling time. The results of the study showed significantly higher intrinsic rate of population increase in insecticides resistant population compared with laboratory susceptible population Lab-PK, Similarly, the resistant population laid more numbers of eggs, which were significantly more viable than susceptible population. The survival to adulthood and doubling time were greater in field populations than the susceptible. The most intriguing finding was that the predation potential of all resistant populations was significantly great compared with Lab-PK. The data point to the fact that resistance to insecticides had positive impact on C. carnea, which could be used in integrated pest management system. The potential for introducing these natural enemies into cropping systems where they have not developed resistance could be a useful tactic for management of various insect pests.

Population cage experiments were employed to detect variability in fitness among Cry2Ab resistant and Cry2Ab susceptible genotypes of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). In two experiments, reciprocal crosses between a Cry2Ab resistant colony (SP15) and a susceptible colony (GR) established populations where the frequency of the allele that conferred resistance was 0.5. Experimental populations were then maintained without exposure to Cry toxins. At the F₂ generation and on later occasions, the pooled egg output from each population was sampled, and emerging neonate larvae were screened to monitor the frequency of the resistant allele. Resistance is recessive so homozygous resistant insects could be readily identified as they are the only genotype to survive and grow when exposed to a discriminating concentration of Cry2Ab toxin. Assuming Hardy—Weinberg equilibrium after the F₁ generation, and the persistence of a 1:1 ratio of resistant and susceptible alleles, one quarter of the populations should be resistant. The populations in the first and second experiment were monitored for five and nine generations, respectively. The cumulative impact of any fitness costs associated with resistant genotypes was expected to result in a decline in the frequency of resistant homozygotes. In both experiments, there was no significant decline in resistance frequencies, and thus the Cry2Ab form of resistance does not seem to exhibit marked fitness costs under laboratory conditions.

Diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), has evolved resistance to various kinds of insecticides in the field. Chlorantraniliprole, which is a new pesticide of the anthranilic diamide group, provides potent and broad-spectrum activity within the insect order Lepidoptera. This insecticide provides a new option for control of P. xylostella populations resistant to other chemicals. The susceptibility of 16 field populations and seven laboratory maintained strains of P. xylostella to chlorantraniliprole were determined through leaf dip bioassay. The susceptibility variation among 16 field populations was low (five-fold), with median lethal concentrations (LC₅₀ values) varying from 0.221 to 1.104 mg/liter. However, wider ranges of variation in LC₅₀ values (10-fold) were observed among seven laboratory strains. Low level tolerance (six- to 10-fold) was detected in two laboratory-selected strains and three field-collected populations when compared with the susceptible Roth strain. A discriminating concentration (15 mg/liter) was calibrated from pooled toxicological data of the 16 field populations, as an important first step in resistance management, for the routine monitoring of resistance in the future. When assessed at the established discriminating dose 15 mg/liter, seven laboratory strains and five field populations showed an average mortality of 99.75% (from 98 to100%). Synergism assays showed metabolic enzymes might be involved in chlorantraniliprole detoxification in the susceptible Roth strain, but not in the additional observed tolerance of strains selected for resistance with other insecticides.

A simulation model of the population dynamics and genetics of western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), was created to evaluate the use of refuges in the management of resistance to transgenic insecticidal corn, Zea mays L., expressing one or two toxin traits. Hypothetical scenarios and a case study of a corn hybrid pyramided with existing toxins are simulated. In the hypothetical situations, results demonstrated that evolution is generally delayed by pyramids compared with deployment of a single-toxin corn hybrid. However, soil insecticide use in the refuge reduced this delay and quickened the evolution of resistance. Results were sensitive to the degree of male beetle dispersal before mating and to the effectiveness of both toxins in the pyramid. Resistance evolved faster as fecundity increased for survivors of insecticidal corn. Thus, effects on fecundity must be measured to predict which resistance management plans will work well. Evolution of resistance also occurred faster if the survival rate due to exposure to the two toxins was not calculated by multiplication of two independent survival rates (one for each insect gene) but was equivalent to the minimum of the two. Furthermore, when single-trait and pyramided corn hybrids were planted within rootworm-dispersal distance of each other, the toxin traits lost efficacy more quickly than they did in scenarios without single-trait corn. For the case study involving transgenic corn expressing Cry34/35Ab1 and Cry3Bb1, the pyramid delayed evolution longer than a single trait corn hybrid and longer than a sequence of toxins based on at least one resistance-allele frequency remaining below 50%. Results are discussed within the context of a changing transgenic corn marketplace and the landscape dynamics of resistance management.

The tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is an economically important pest of the Americas. Females of this species copulate multiple times during their lifetimes, and the presence of sperm from multiple males inside them could allow for a diversity of paternal genotypes in the offspring, unless there was complete precedence of sperm from the first mating. if a female copulates with a male that is insecticide-susceptible and another male that is insecticide-resistant, her progeny could vary in their resistance phenotypes. In some cases, this could impact the evolution of insecticide resistance in a population. We designed a series of experiments to determine whether Bacillus thuringiensis susceptibility is maintained when an H. virescens female that is homozygous for a genetically recessive form of B. thuringiensis resistance copulates with a Cry1Ac-susceptible and a Cry1Ac-resistant males. During the lifetime of double-copulated females, a proportion of F₁ progeny were Cry1Ac-resistant. This indicates that when a B. thuringiensis-resistant H. virescens female copulates with two males, with one male being resistant to Cry1Ac, some of the progeny will carry resistance to this insecticide. Due to the polyandrous nature of this species, the above-mentioned scenario is not unrealistic; therefore, results from this study may help understand and manage the evolution of B. thuringiensis-resistance in field populations.

Limited information exists on the insecticide susceptibility of redbanded stink bug, Piezodorus guildinii (Westwood) (Heteroptera: Pentatomidae), despite its impact on soybean, Glycine max (L.) Merr., production in Brazil and the United States. Therefore, this study set out to 1) determine baseline levels of susceptibility to currently recommended pesticides using topical and vial bioassays, 2) determine the levels of esterase activity in populations in the United States and Brazil, and 3) compare control among products in field trials. In topical bioassays conducted in the United States using technical grade materials, the LC₅₀ values of lambda-cyhalothrin, acephate, and methamidophos were 4–25, 141–295, and 40–151 ng per insect, respectively. The LC₅₀ values of imidacloprid and thiamethoxam were 11 and 27 ng per insect, respectively. In vial bioassays conducted in the United States using technical grade materials, the LC₅₀ values of cypermethrin, acephate, and methamidophos were 0.4–0.9, 3.8, and 1.6 µg per vial, respectively. In topical bioassays conducted in Brazil by using commercially formulated products, the LC₅₀ values of acephate, methamidophos, endosulfan, and imidacloprid were 0.90–1.9, 0.4–0.6, 1.5–6.6, and 0.2–0.3 µg per insect, respectively. In vial bioassays conducted in Brazil using commercially formulated products, the LC₅₀ values of endosulfan, methamidophos, and lambda-cyhalothrin were 4–32 and 2–24 µg/cm² for thiamethoxam and imidacloprid. Esterase activity in Louisiana (United States) populations ranged from 251 to 658 nmol alpha-naphthol formed/min/mg protein. Esterase activity levels in Londrina (Brazil) populations averaged 163 nmol/min/mg. In field tests, P. guildinii in Louisiana were controlled by organophosphates thiamethoxam and imidacloprid and in Brazil, with combinations of neonicotinoids and pyrethroids.

Over the past three decades, Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become a major worldwide pest of many agricultural and horticultural crops. In response, much time, money, and effort have been put into pure and applied research focusing on the biology and control of this pest, Western flower thrips is native to Western North America and widespread in California. High levels of variation in basic biology, pest status, and resistance to insecticides bring into question the specific status of Western flower thrips. We used nuclear-mitochondrial barcoding to compare DNA sequences of nuclear and mitochondrial genes between Western flower thrips populations across California, looking for association between these unlinked loci. Sequences of D2 domain of 28S and cytochrome c oxidase I gene revealed the existence of two distinct but sympatric genetic entities, and we describe a simple polymerase chain reactionbased method for diagnosing these entities. The complete association of these nuclear and mitochondrial loci in areas of sympatry is indicative of reproductive isolation and the existence of two cryptic species, both of which key out to Western flower thrips by using morphological characters. The finding that Western flower thrips is a complex of two species has important implications for past, current, and most importantly future research on these pests.

Symbiosis allows an insect access to unbalanced food sources on which other organisms cannot survive. A bacterial endosymbiont, Buchnera aphidicola, gives aphids the ability to feed on phloem depleted of certain essential amino acids by producing those required. Pseudogenes and lower plasmid copy numbers of essential amino acid genes in B. aphidicola, endosymbiont of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), suggest that this symbiotic relationship is degenerating. The complete endosymbiont assemblages, copy numbers of plasmids (important in essential amino acid production), and sequence variation in B. aphidicola, from 10 Russian wheat aphid biotypes, were investigated. B. aphidicola was found to be monosymbiotic in the Russian wheat aphid biotypes and other Diuraphis species examined. An insert, occurring in an inverted repeat region on the leucine plasmid, was the only variation found in the ≈10-kb B. aphidicola sequence analyzed from each Russian wheat aphid biotype. This inverted repeat was shown previously to be conserved within the family Aphididae. The insert occurred in B. aphidicola sequences isolated from four Russian wheat aphid biotypes. Copy numbers of the leucine plasmid differ between the South African and U.S. biotypes and were similar to previously reported values for biotypes from the same geographic regions. These results suggest that B. aphidicola may still contribute to Russian wheat aphid fitness when the aphid feeds on a variety of hosts.

A couple of different members of the coleopteran genus Otiorhynchus (Coleoptera: Curculionidae) are becoming increasingly important as pests of nursery and ornamental plants in global horticulture. Although adult weevils are morphologically distinguishable by skilled personnel, high potential for misidentification is given for cryptic larval stages. For developing and applying efficient pest management strategies the determination of the respective species is however a prerequisite, because each species may have a different phenology or a varying susceptibility to pesticides. Here, we report on the development of a diagnostic polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for differentiation among 16 Otiorhynchus and seven other weevil species independent of their developmental stage. An ≈780-bp fragment of the mitochondrial cytochrome oxidase subunit II was amplified and subsequently digested with at most four restriction enzymes generating species-specific fragment patterns. The assay was validated on a total of 127 individuals and the obtained fragment patterns correctly identified 23 different weevil species. The PCR-RFLP method reported here is cost-effective, robust, and fast and could be used in the future by plant protection services for diagnostic purposes.

We genetically characterized Encarsia diapsidicola Silvestri and Encarsia berlesei Howard (Hymenoptera: Aphelinidae) by two molecular methods: phylogenetic analysis of the cytochrome oxidase subunit I gene (COI) and intersimple sequence repeat-polymerase chain reaction (ISSR-PCR) DNA fingerprinting. These two closely related endoparasitoids are candidate biological control agents for the white peach scale, Pseudaulacaspis pentagona Targioni-Tozetti (Hemiptera: Diaspididae), in Hawaii. We developed species-specific COI molecular markers that discriminated the two species, and we tested the utility of the E. diaspidicola-specific COI marker to detect parasitism of white peach scale. The COI sequence data uncovered 46-bp differences between the two Encarsia spp. The level of COI genetic divergence between the two species was 9.7%, and the two clustered into their own clade on a parismonious phylogram. ISSR-PCR readily discriminated the two Encarsia spp. because each was observed with fixed species-specific banding patterns. The COI molecular markers were specific for each species because cross-reactivity was not observed with nontarget species. The E. diaspidicola-specific COI markers were successful at detecting parasitism of white peach scale by E. diaspidicola by 24 h. Both molecular marker types successfully discriminated the two Encarsia spp., whereas the COI markers will be useful as tools to assess levels of parasitism in the field and to study competitive interactions between parasitoids.

A genetic stock certification assay was developed to distinguish Russian honey bees from other European (Apis mellifera L.) stocks that are commercially produced in the United States. In total, 11 microsatellite and five single-nucleotide polymorphism loci were used. Loci were selected for relatively high levels of homogeneity within each group and for differences in allele frequencies between groups. A baseline sample consisted of the 18 lines of Russian honey bees released to the Russian Bee Breeders Association and bees from 34 queen breeders representing commercially produced European honey bee stocks. Suitability tests of the baseline sample pool showed high levels of accuracy. The probability of correct assignment was 94.2% for non-Russian bees and 93.3% for Russian bees. A neighbor-joining phenogram representing genetic distance data showed clear distinction of Russian and non-Russian honey bee stocks. Furthermore, a test of appropriate sample size showed a sample of eight bees per colony maximizes accuracy and consistency of the results. An additional 34 samples were tested as blind samples (origin unknown to those collecting data) to determine accuracy of individual assignment tests. Only one of these samples was incorrectly assigned. The 18 current breeding lines were represented among the 2009 blind sampling, demonstrating temporal stability of the genetic stock identification assay. The certification assay will be used through services provided by a service laboratory, by the Russian Bee Breeders Association to genetically certify their stock. The genetic certification will be used in conjunction with continued selection for favorable traits, such as honey production and varroa and tracheal mite resistance.

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), a worldwide pest of onion, Allium cepa L., can reduce onion yield by >50% and be even more problematic when it transmits Iris yellow spot virus (family Bunyaviridae, genus Tospovirus, IYSV). Because T. tabaci is difficult to control with insecticides and other strategies, field studies on onion, Allium cepa L., resistance to T. tabaci and IYSV were conducted in 2007 and 2008 in two locations in New York state. Forty-nine cultivars were evaluated for resistance by counting the number of larvae weekly and recording leaf damage. In another experiment, the impact of T. tabaci and IYSV on plant growth and yield was examined by spraying half of the plants with an insecticide. Eleven of the 49 cultivars had very little leaf damage and were considered resistant to T. tabaci. Visual assessment indicated that all resistant cultivars had yellow-green— colored foliage, whereas the other 38 had blue-green—colored foliage. The visual assessment of color agreed with data on color taken with a HunterLab Ultra Scan XE colorimeter. The onions ‘Colorado 6’ and ‘NMSU 03-52-1’ had the lowest numbers of T. tabaci, suggesting strong antibiosis and/or antixenosis. The other nine cultivars had variable numbers of T. tabaci, indicating a possible combination of categories of resistance. In the nonprotected treatments there were significant reductions in plant height and plant weight in most of the resistant cultivars, but there were reductions in bulb weight only in a few of them. The average of plants infected with IYSV was 10% in 2007 and 60% in 2008. Our findings indicate potential for developing onion resistance to T. tabaci as part of an overall integrated pest management strategy but suggest difficulties in identifying resistance to IYSV.

The Russian wheat aphid, Diruaphis noxia (Kurdjumov) (Hemiptera: Aphididae), is globally one of the most devastating pests of bread wheat, Tritium aestivum L.; durum wheat, Triticum turgidum L.; and barley, Hordeum vulgare L. Host plant resistance is the foundation for cereal insect pest management programs, and several sources of D. noxia resistance have been incorporated in cultivars to manage D. noxia damage. The emergence of D. noxia North American biotype 2 (RWA2) in Colorado has made all known Dn genes vulnerable except the Dn7 gene from rye, Secale cereale, and has warranted exploration for sources of resistance to both RWA1 and RWA2. The category of resistance in resistant donor plants may exert selection pressure over the aphid population to form a new virulent population. In the current study, we report tolerance and antibiosis resistance to RWA1 and RWA2 in the barley genotype ‘Stoneham”. The rate and degree of expression of resistance in Stoneham against RWA1 and RWA2, although not similar, are greater than the partial resistance in ‘Sidney’. Antixenosis resistance to RWA1 or RWA2 was not observed in Sidney or Stoneham. The tolerance identified in Stoneham is encouraging because it may delay D. noxia biotype selection and fits well in a dryland barley cropping system.

The soybean aphid, Aphis glycines Matsumura, is a pest of cultivated soybean, Glycine max (L.) Merr., in North America. Recent developments in host plant resistance studies have identified at least four soybean aphid resistance genes (Rog1–4) and two soybean aphid biotypes (biotype 1 and 2), defined by differential survivability on resistant soybean. Detached soybean leaves were tested as a more rapid and practical assay to assess host plant resistance and virulence. Two susceptible lines (‘Wyandot’ and ‘Williams 82’) and two resistant lines (PI 243540 and PI 567301B) were examined. Various life history characteristics were compared among aphids on whole plants and detached leaves. Results indicated that resistance to soybean aphid was lost using detached leaves of PI 567301B but retained with PI 243540. To test for aphid virulence, net fecundities were compared among biotype 1 and biotype 2 after rearing on detached leaves of the resistant ‘Jackson’ (to which biotype 2 is virulent). A significant difference was detected in net fecundities among biotypes on detached leaves of Jackson and used to predict growth rates and virulence from 30 field-collected individuals of unknown virulence. No field individuals matched biotype 2 predictions, but four individuals had higher net fecundities than biotype 2 predictions (13%) and could be considered moderately virulent. The results indicated that the retention of soybean aphid resistance in detached leaves is dependent on PI and resistant source, but if resistance is retained, detached leaves could be used to determine soybean aphid virulence.

The Russian wheat aphid, Diruaphis noxia. (Kudjumov) (Hemiptera: Aphididae), is globally one of the most devastating pests of bread wheat, Tritium aestivum L., durum wheat, Triticum turgidum L., and barley, Hordeum vulgare L. Several sources of D. noxia resistance have been incorporated in commercial wheat and barley genotypes, but up to eight virulent biotypes, defined based on their ability to damage different wheat and barley genotypes, now occur across the western United States since the first appearance of D. noxia in North America in 1986. Critical to the study of D. noxia and other invasive species is an understanding of the number and origin of invasions that have occurred, as well as the rate or potential of postinvasion adaptation and geographic range expansion. The goal of this study was to determine whether D. noxia biotypes are by-products of a single invasion or multiple invasions into North America. We used the genome-wide technique of amplified fragment length polymorphisms, in combination with 22 collections of D. noxia from around the world, to assess this question, as well as patterns of genetic divergence. We found multiple lines of evidence that there have been at least two D. noxia invasions of different origin into North America, each resulting in subsequent postinvasion diversification that has since yielded multiple biotypes.

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is an important and ubiquitous pest of potato, Solanum tuberosum L. (Solanaceae), in both field and stores in the subtropical and tropical zones. The evaluation of potato tubers for susceptibility to potato tuberworm, by measuring its life table parameters, is a valuable component of integrated pest management (IPM). Potato tuberworm life table parameters were investigated in laboratory at 24 ± 1°C, 65 ± 5% RH, and a photoperiod of 8:16 (L:D) h on six commonly grown potato cultivar tubers: ‘Agria’, ‘Burren’, ‘Savalan’, ‘Marfona’, ‘Sante’, and ‘Picaso’. No food was provided to feeding adult moths during experiments. The survival rate on Savalan and Burren potatoes was higher than on other cultivars. The highest reproductive rate was observed on Burren potatoes (50.739 ± 2.45), although there was one statistical group for net reproduction rate (R_o). The mean generation time (T_o) was the longest on the Agria potatoes. The significant difference was observed between intrinsic rates of increase (r_m) on the potato cultivars. The mean generation time has reciprocal relation with r_m; subsequently. the lowest intrinsic rate of increase was observed on Agria potatoes. The highest and lowest r_m value was observed on Burren and Agria potatoes, respectively. The descending order of intrinsic rates of increase was on Burren, Savalan, Sante, Marfona, Picaso, and Agria potaotes. The lowest r_m value indicates that Agria is a relatively insusceptible compared with the other cultivars tested and that this cultivar can be used effectively in sustainable IPM.

In French Guiana, malaria transmission is mainly due to Anopheles darlingi Root, but other species also are involved. Investigation and surveillance must be carried out on all the species to unravel malaria transmission patterns. In this study, we aimed to compare the ability of Mosquito Magnet- and CDC-Light Trap-based methods and human landing collection for evaluating abundance of Anopheles species. Human landing collections exhibited the best results, followed by the Mosquito Magnet and the CDC-Light Trap methods. Studies have to be done to further investigate these methods and other traps have to be tested.

The insecticidal effect of Heterorhabditis bacteriophora Poinar (Nematoda: Heterorhabditidae), Steinernema carpocapsae (Weiser) (Nematoda: Steinernematidae), and Steinernema feltiae (Filipjev) (Nematoda: Steinernematidae) against Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) (larvae), lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) (adults), rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) (adults), and confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) (adults and larvae) was examined under laboratory conditions in wheat, Triticum aestivum L. The nematodes were applied at the following doses: 0 (control), 100, 500, 1,000, 1,500, 5,000, 10,000, and 20,000 infective juveniles (IJs) per ml, corresponding to 10, 50, 100, 150, 500, 1,000, and 2,000 IJs per insect, and their infectivity was tested at 20 and 30°C after 4 and 8 d of exposure. For E. kuehniella larvae wheat treatments with S. feltiae provided mortality that ranged from 36.7 to 78.3% whereas no mortality was noted in the treatment with S. carpocapsae at 100 IJs per ml at 20 or at 30°C. Also, at 20°C, in wheat treated with H. bacteriophora at 100 IJs per ml, very few larvae were dead. For R. dominica adults, at 20°C, the mortality of adults in wheat treated with S. feltiae and S. carpocapsae did not exceed 23.3 and 41.7%, respectively, at 20,000 IJs per ml, with no significant differences among doses. In the case of S. oryzae adults, the mortality was very low at all doses, and temperatures and did not exceed 9%. Mortality of T. confusum adults did not exceed 17% regardless of the entomopathogenic nematode species tested. In contrast, mortality of T. confusum larvae was notably higher and exceeded 56% in wheat treated with 10,000 or 20,000 IJs per ml of S. feltiae at 20°C. Unlike S. feltiae and S. carpocapsae, the application of H. bacteriophora resulted in lower mortality levels. Generally, the increase of temperature reduced the mortality levels of the T. confusum larvae. In most cases, the efficacy level of the tested entomopathogenic nematode species increased with the dose and decreased with the increase of temperature.

Differences in stored-product psocid progeny production as a function of commodity type, percentage of cracked kernels, and wheat class were examined using laboratory bioassays. Population growth of Liposcelis bostrychophila Badonnel, Liposcelis decolor (Pearman), Liposcelis paeta Pearman, and Liposcelis entomophila (Enderlein) (Psocoptera: Liposcelididae) was highest on sorghum Sorghum bicolor (L.) Moench, followed by wheat, Triticum aestivum L., and rice, Oryza sativa L., whereas progeny production was negligible on wheat germ. In a second experiment that did not include L. entomophila, population growth was examined on wheat containing 0, 1, 5, 10, 20, 50, and 100% cracked kernels. Progeny production did not increase as cracked kernel content increased. Instead, progeny production peaked at 20% for L. bostrychophila adults and nymphs, at 10% for L. decolor, and at 50% for L. paeta adults; no further increases were noted beyond these levels of cracked wheat content. In a third experiment that did not include L. entomophila, progeny production was examined on eight classes of wheat: hard red winter, hard red spring, soft white winter, soft white spring, soft club, durum, soft red winter, and hard white. Overall, progeny production was higher on durum wheat than on the other classes. The results indicate that there are considerable variations in psocid population growth among the different commodities tested, and this information may be used to predict the degree to which stored commodities are susceptible to psocid infestation.

Data from long-term Tribolium castaneum (Herbst) pheromone trapping programs in two flour mills was used to evaluate the impact of structural fumigations (n = 23) on pest populations. The two mills differed in mean number of beetles captured and proportion of traps with captures of one or more beetles, but in one of the mills the mean number of beetles captured was reduced after implementing a more intensive integrated pest management program. Mean number of beetles per trap and proportion of traps with captures increased by 52.7 ± 8.2 and 24.8 ± 4.7% from one monitoring period to the next but decreased by 84.6 ± 4.6 and 71.0 ± 5.1% when fumigation occurred between periods, respectively. Mean number of beetles per trap and proportion of traps with captures immediately after fumigation were both positively correlated with number captured per trap and proportion of traps with captures in the monitoring period immediately before fumigation. Mean daily air temperature inside the mill fluctuated with the season, and although always warmer than the outside temperature, the relative difference varied with season. Relationship between inside and outside temperature could be explained well by an exponential equation with the parameters a = 20.43, b = 2.25, and c = -15.24 (r² = 0.6983, which is 94% of the maximum r² obtainable). Although outside temperature differed between spring and fall fumigations, inside temperature and reduction in beetle captures was not affected by season. A better understanding of pest populations and the impact of structural treatments within commercial food facilities is critical for improving the management of pest populations and for the adoption of methyl bromide alternatives.

Structural fumigations of food processing plants to manage stored-product insects has been a major component of pest management programs, but limited information on field efficacy is available. Efficacy, based on pheromone trapping data, consists of initial reduction in captures after treatment and rebound in trap captures over time. Pattern of Tribolium castaneum (Herbst) rebound was evaluated after 21 fumigations in two flour mills. Rebound in mean number of beetles captured and the probability of a trap capturing one or more beetles was evaluated. Rebound to a threshold mean beetle capture of 2.5 beetles per trap per 2-wk period took 174 ± 33 d and rebound took longer after fall (248 ± 50 d) than spring (104 ± 21 d) fumigations. Rebound to the probability of capture threshold of 0.50 was 120 ± 21 d, but there was no significant effect of season. Improvement in integrated pest management (IPM) practices in one of the mills was associated with an increase in time to reach mean beetle capture threshold (49 ± 15 d before and 246 ± 71 d after) but not in time to reach the probability of capture threshold (38 ± 14 d before and 165 ± 46 d after). There was a negative correlation between number captured after fumigation and time to rebound to threshold. After improved IPM there was a significant reduction in the number of beetles per trap immediately after fumigation. Above these two thresholds the degree of change in trap captures is significantly greater than below, which suggests they might be useful in evaluating risk in a pest management program.

Starch gel electrophoresis of isozymes was used to estimate gene flow among nine populations of Stomoxys calcitrans (L.) (Diptera: Muscidae) from Thailand. Of the 13 putative loci, nine polymorphic loci were detected. Limited genetic differentiation among populations was observed (F_ST = 0.060). The highest level of polymorphism was observed in flies from eastern Trat and northern Chiang Mai provinces (69.2%), whereas the lowest level of polymorphism was seen in flies from central Saraburi Province (23.1%). Gene flow between populations varied from 3.27 to 27.53 reproductive migrants per generation. Among the nine populations sampled, no correlation was seen between genetic and geographical distances showing that sampled S. calcitrans fit closely in the same cluster taxa. The electrophoresis of ten isozymes shows a genetic homogeneity of S. calcitrans populations at the scale of Thailand.

We screened 85 isolates of Bacillus thuringiensis (Berliner), making up 57 different subspecies, and two isolates of Bacillus sphaericus (Meyer and Neide) for activity against immature horn flies, Haematobia irritons (L.), and stable flies, Stomoxys calcitrans (L.). The majority of B. thuringiensis and the B. sphaericus isolates had little or no activity against horn fly and stable fly. Approximately 87% of the isolates caused <50% mortality of horn fly larvae and 64% caused <25% mortality. For stable fly, 95% of the isolates caused <50% mortality, and 93% caused <25% mortality. Five isolates were highly toxic to horn fly and stable fly immatures. These isolates were B. t. tolworthi 4L3, B. t. darmstadiensis 4M1, B. t. thompsoni 4O1, B. t. thuringiensis HD2, and B. t. kurstaki HD945. The LD₅₀ values ranged from 2.2 to 7.9 × 10⁶ spores per g manure for horn fly and from 6.3 to 35 × 106 spores per g media for stable fly. These were consistently more toxic compared with the B. t. israelensis isolates examined. All had DNA that hybridized with cry1Aa, cry1Ab, and cry1Ac toxin probes, three hybridized with a cry1B probe, and two hybridized with a cry2A probe. These may have potential for use in integrated management of pest flies.